Baffle for texturing jet and method

ABSTRACT

A method and apparatus to automatically adjust baffle setting for variations in processing conditions when using a yarn treating fluid jet having a baffle adjacent its outlet end. The baffle is mounted for free movement toward and away from the outlet end of the jet and defines with the adjacent outlet end surface of the jet a mutually shared area greater than the crosssectional area of the exit of the treatment channel of the jet. The baffle is mounted at a position of equilibrium with respect to the fluid flow rate from the jet and can automatically adjust for minor changes in flow rate to maintain uniform operability.

United States Patent 11 1 Koslowski 1 1 Sept. 17, 1974 [5 BAFFLE FOR TEXTURING JET AND 2,932,935 4/1960 Richmond et al. 28/l.4 x METHOD 3,217,482 [H1965 Baer 28/l.3 x

[75] Inventor: lg/izliirtigeilagmter Koslowski, Geneva, Primary Emml-ner Louis K. Rimrodt [73] Assignee: E.I. du Pont de Nemours and [57] ABSTRACT Company wllmmgton A method and apparatus to automatically adjust baffle 22 Filed; Dec. 15 972 setting for variations in processing conditions when using a yarn treating fluid jet having a baffle adjacent [21] APPL N05 315,563 its outlet end. The baffle is mounted for free movement toward and away from the outlet end of the jet 52 US. Cl. 2s/1.4, 28/7212 and defines t the adjacent Outlet end Surface of the [51 Int. Cl D02g l/l6 J a mutually Shared area greater than the Cross- 5 Field f Search 2 3 1.4, 72 7 sectional area of the exit of the treatment channel of the jet. The baffle is mounted at a position of equilib- 5 References Cited rium with respect to the fluid flow rate from the jet UNITED STATES PATENTS and can automatically adjust for minor changes in flow rate to maintain uniform operability. 2,638,146 5/1953 Rounsevllle et al. 28/72.]2 X 2,874,444 2/1959 Griset 28/l.4 5 Claims, 5 Drawing Figures 1 S 1 E '8 4 a 1 BAFFLE FOR TEXTURING JET AND METHOD BACKGROUND OF THE INVENTION This invention relates to a method and apparatus for treating a yarn with high velocity fluid to increase the bulk of said yarn. More particularly, it concerns texturing yarn while maintaining a baffle in closely spaced relation to the exit of a fluid jet device by a balance of fluid forces.

Certain fluid jet processes for bulking or texturing yarn have employed plates positioned at various distances from the jet exit and at various angles to the yarn path to deflect the yarn and fluid from a straight path. Such a plate may be useful for separating the air from the yarn, for reducing the tension on the yarn while it is in the turbulent jet to improve the bulking action and to control the uniformity of the yarn product. These plates normally are in a fixed position relative to the jet during operation.

Stringup of such a jet is difficult. In addition, small variations in the distance of a fixed baffle from the jet, i.e., the initial setting may give large variations in operability and texturing effect, from jet-to-jet on a multiposition machine especially when the desired position of the baffle is very close to the jet.

The present invention provides a method and apparatus to automatically adjust for such small variations in initial settings and thus hold to a minimum variations in operability and texturing from position-to-position.

SUMMARY OF THE INVENTION It has now been found that when a baffle having a surface area that defines with the adjacent outlet end surface of a jet texturing device a mutually shared area greater than the cross-sectional area of the jet treatment channel of the outlet of the jet is free to move toward and away from the outlet end and is brought close to the outlet of the jet, the fluid flowing through the gap mutually defined by the adjacent baffle and jet surfaces has a pressure below atmospheric. Atmospheric pressure on the side of the baffle remote from the jet will force the object toward the jet until it reaches an equilibrium position under the influence of forces exerted by fluid and yarn against the side of the object near the jet device.

BRIEF DESCRIPTION OF THE DRAWING FIGS. 4 and show alternate arrangements of a baffle plate.

DESCRIPTION OF THE PREFERRED EMBODIMENT In the drawings, yarn 1 enters a jet device 2 through yarn entrance passage 3. Compressed air or other fluid at room temperature enters jet device 2 through pipe 4 and impinges on yarn l at the entrance to treatment channel 5 where the yarn and high velocity fluid travel together to the exit 6 of the treatment channel which has a cross-sectional area 14. As yarn 1 and the fluid emerge from exit 6 together, they strike baffle plate 8 which in this instance is pivoted to swing freely about hinge point 9. Surrounding exit 6 is end surface 7 of jet device 2.

FIG. 2 shows the exit end of a jet device in greater detail. When the yarn l and the texturing fluid impinge on baffle plate 8, they exert a certain force F tending to push baffle plate 8 away from the jet exit. The fluid divides and flows away from exit 6 through the space between end surface 7 and baffle plate 8. The velocity of this fluid flow will depend chiefly upon the flow rate of the fluid, the distance between the baffle plate and end surface 7 and the cross-sectional area of the flow path. Due to its velocity, the exiting fluid will have a dynamic pressure lower than atmospheric, in compliance with the Bernouilli Principle. This lower pressure, which will usually vary in magnitude from point-to-point along the fluid flow path, will be exerted on the baffle plate over area 13 of the gap between end surface 7 and baffle 8. If baffle 8 is smaller than end surface 7, the extent of area 13 will be limited by the baffle. Thus, area 13 is the area shared mutually by end surface 7 and baffle 8. The force F is the total force exerted by each increment of fluid pressure on baffle 8 over area 7 multiplied by the increments of area 7 over which each pressure increment acts.

If area 13 is very small, force F acting over area 14 will predominate and will push the baffle plate away from the jet. However, it has been found that if area 13 exceeds area 14, the algebraic sum of F and F will usually be lower than the force F exerted by atmospheric pressure on the outer side of the baffle plate, and F will move the baffle plate toward the jet until it reaches a position of equilibrium. Preferably, area 13 should be more than twice area 14 to'maintain a substantial excess of force holding the baffle near the jet, so that the baffle is not likely to be knocked away from the jet accidently.

In FIG. 3, transparent circular baffle 8 is smaller than outlet end surface 7 of the jet. However, area 13 mutually shared by end surface 7 and bafile 8 over which the reduced pressure acts, is seen to be appreciably larger than the cross-sectional area 14 of the yarn treatment channel or passage exit 6.

FIG. 4 shows an alternate position of baffle plate 8. Under certain circumstances, as when very bulky yarns are being made, the baffle when in the equilibrium position may unduly restrict the passage of the yarn. In such a case, hinge point 9 may be moved closer to jet device 2 so that baffle plate 8 contacts jet device 2 at point 10, thus providing a means for limiting the travel of baffle plate 8 toward the outlet end of the jet and providing a wedge shaped space for yarn and air to exit. To be effective in such cases, the included angle a between the baffle and outlet end of the jet should not exceed 7. The alternate ways of limiting the travel of baffle plate 8toward jet device 2, such as bending the baffle or inserting a stop screw in jet device 2 are readily apparent.

FIG. 2 shows a baffle plate considerably larger than the end surface 7 of jet device 2. Alternatively, the end surface 7 of jet device 2 may be very large and the area of the baffle plate adjacent to the exit area may be re-- duced to adjust the position of equilibrium as in FIG. 3. Thus, the position of equilibrium may be varied by varying such factors as the fluid flow rate, the yarn mass, the yarn velocity, area 14 of passage exit 6, the end surface 7 of jet device 2, the area of the baffle plate 8 and the angle between the baffle plate and the end surface of the jet device.

In FIG. 5, the jet device has a small projection 11 surrounding exit 6 of treatment channel 5. The fluid force F in this instance will be the sum of a first force due to the flow of fluid between the end of projection 11, a very small area and the baffle plate and a second force due to the flow of fluid through the wider gap of much larger area between surface 12 and the baffle plate.

The equilibrium position usually varies to some extent during operation as the fluid forces and particularly the impact of the yarn on the baffle plate 8 vary, causing some oscillation of the baffle plate. Such oscillation may be damped, if desired, by such means as increasing the mass of baffle plate 8 or other usual engineering means for avoiding resonant conditions.

While the provision of hinge point 9 is one convenient way to support a baffle plate, the baffle plate may, for example, be a disc free to float toward and away from jet device 2, subject only to caging or similar restraint to restrict its movement to the desired operating range.

The baffle may be an object other than a flat plate, for example, a sphere of sufficient diameter to form a narrow gap with the end of the jet device and of sufficient mutual area 13 at the gap to produce an adequate low pressure zone for maintaining an equilibrium condition. Particularly, when the baffle object has a shape other than flat, the outlet end surface of the jet may be of shapes other than flat to obtain desired fluid flow conditions in the gap and to control the movement of yarn through the gap.

The jet device may also be operated in any position provided that area 13 be adjusted to compensate for the force of gravity on baffle object 8, or that counterdesigned so that the sphere may float freely and maintain position by aerodynamic forces alone without a mechanical restraint.

End surface 7 is usually perpendicular to the axis of treatment channel 5, but other angles may be employed.

The invention has improved the texturing of other materials such as glass, polyamide, polyester and rayon yarns in single end, parallel and core (differential feed rate) texturing in a wide range of deniers using either dry or wet feed yarns. Although invention has been disclosed using fluid at room temperature, fluid at elevated temperatures may also be used.

What is claimed is:

1. In a yarn treating apparatus including a jet having inlet and outlet ends connected by a passage through which yarn together with fluid passes for treatment, the improvement comprising: a baffle mounted adjacent to said outlet end for free movement toward and away from said outlet end, said baffle having a surface facing said outlet end, said baffle surface defining with said outlet end a mutually shared area greater in area than the cross-sectional area of the passage at said outlet end.

2. The apparatus of claim 1, said baffle being spaced from said passage at said outlet end.

3. The apparatus as defined in claim 2, said baffle being pivotally mounted for swinging movement toward and away from said outlet end.

4. The apparatus as defined in claim 1, including means for limiting the travel of the baffle toward the outlet end of the jet.

balancing be provided when a hinge point 9 is em- 0 jet at a location of equilibrium for the baffle at said ployed. When the baffle object is a sphere and the jet device exhausts vertically upward, the jet exit may be 

1. In a yarn treating apparatus including a jet having inlet and outlet ends connected by a passage through which yarn together with fluid passes for treatment, the improvement comprising: a baffle mounted adjacent to said outlet end for free movement toward and away from said outlet end, said baffle having a surface facing said outlet end, said baffle surface defining with said outlet end a mutually shared area greater in area than the cross-sectional area of the passage at said outlet end.
 2. The apparatus of claim 1, said baffle being spaced from said passage at said outlet end.
 3. The apparatus as defined in claim 2, said baffle being pivotally mounted for swinging movement toward and away from said outlet end.
 4. The apparatus as defined in claim 1, including means for limiting the travel of the baffle toward the outlet end of the jet.
 5. In a method for operating a yarn treating jet that includes passing yarn together with high velocity fluid through the jet passage from its inlet to its outlet end at a fixed rate and impinging the yarn and fluid against a baffle located near the outlet end of the jet the improvement comprising: mounting said baffle for free movement toward and away from the outlet end of the jet at a location of equilibrium for the baffle at said fixed flow rate. 